Corvis (temp bot name) rough ideas.

[maddox10]

Hannibalito 4 uses a 78mm bore FP ram.
Containing those 2.5 tons of force ain't that easy.

[grant_ploughbot]

In our Robo Challenge arena we have a 4mm hardox floor which means magnets are a good bet and alot of people use them. In heavies, Its probably not worth looking at as the wooden floors get damaged and your likely to be sucking in bits of dust, broken bits of MDF/Plywood etc and cause your self problems.